Re: Permission denied when chainbuilding packages with mock

[Julian Sikorski <belegdol@gmail.com>]

Am 10.11.21 um 12:23 schrieb Julian Sikorski:
> W dniu 10.11.2021 o 08:56, Steve French pisze:
>> Fix for the kernel client attached
>>
>>
>> On Tue, Nov 9, 2021 at 6:54 PM Jeremy Allison <jra@samba.org> wrote:
>>>
>>> On Tue, Nov 09, 2021 at 10:26:59AM +0100, Julian Sikorski wrote:
>>>> Am 09.11.21 um 09:10 schrieb Steve French:
>>>>> Yes - here is a trivial reproducer (excuse the ugly sample 
>>>>> cut-n-paste)
>>>>>
>>>>> #include <stdio.h>
>>>>> #include <stdlib.h>
>>>>> #include <unistd.h>
>>>>> #include <string.h>
>>>>> #include <fcntl.h>
>>>>> #include <sys/types.h>
>>>>> #include <sys/stat.h>
>>>>>
>>>>> int main(int argc, char *argv[]) {
>>>>> char *str = "Text to be added";
>>>>> int fd, ret, fsyncrc, fsyncr_rc, openrc, closerc, close2rc;
>>>>>
>>>>> fd = creat("test.txt", S_IWUSR | S_IRUSR);
>>>>> if (fd < 0) {
>>>>> perror("creat()");
>>>>> exit(1);
>>>>> }
>>>>> ret = write(fd, str, strlen(str));
>>>>> if (ret < 0) {
>>>>> perror("write()");
>>>>> exit(1);
>>>>> }
>>>>> openrc = open("test.txt", O_RDONLY);
>>>>>          if (openrc < 0) {
>>>>>                  perror("creat()");
>>>>>                  exit(1);
>>>>>          }
>>>>> fsyncr_rc = fsync(openrc);
>>>>> if (fsyncr_rc < 0)
>>>>> perror("fsync()");
>>>>> fsyncrc = fsync(fd);
>>>>> closerc = close(fd);
>>>>> close2rc = close(openrc);
>>>>> printf("read fsync rc=%d, write fsync rc=%d, close rc=%d, RO close
>>>>> rc=%d\n", fsyncr_rc, fsyncrc, closerc, close2rc);
>>>>> }
>>>>>
>>>>
>>>> I can confirm this fails on my machine without nostrictsync:
>>>>
>>>> $ ./test
>>>>
>>>> fsync(): Permission denied
>>>>
>>>> read fsync rc=-1, write fsync rc=0, close rc=0, RO close rc=0
>>>>
>>>> and works with nostrictsync:
>>>>
>>>> $ ./test
>>>>
>>>> read fsync rc=0, write fsync rc=0, close rc=0, RO close rc=0
>>>>
>>>> So is the bug in the Linux kernel?
>>>
>>> Yes, it's in the kernel cifsfs module which is forwarding an 
>>> SMB_FLUSH request
>>> (which the spec says must fail on a non-writable handle) to
>>> a handle opened as non-writable. Steve hopefully will fix :-).
>>
>>
>>
> Thank you. I can confirm that 5.15.1 kernel with this patch applied [1] 
> works both with the test case you provided earlier as well as with mock 
> chainbuilds without the need for the nostrictsync mount option. Fedora 
> kernel-5.14.16-301.fc35.x86_64 was failing without it.
> 
> Tested-by: Julian Sikorski <belegdol@gmail.com>
> 
> Best regards,
> Julian
> 
> [1] https://gitlab.com/belegdol/kernel-ark/-/commits/fedora-5.15-cifs-fix/

Hi,

may I ask what the usual process of getting the patch into the Linus's 
tree and to the stable branches is? If it takes longer, I am going to go 
back to nostrictsync for now.

Best regards,
Julian